<u># 用法</u>
<em>绕 axis 轴旋转</em>
<u># 语法</u>
<em>Object3D</em>.<b>rotateOnAxis</b>(<s>axis</s>, <s>angle</s>)
<u># 参数</u>
<s>axis</s> ：	<em>必需，三维向量</em>（<u> new Three.Vector3(0,0,0)</u>）<em>值为0或1</em>
<s>angle</s> ：	<em>必需，旋转角度</em>(<u>Number</u>)
<u># 示例</u>
<em>Object3D</em>.<b>rotateOnAxis</b>(<s>new Three.Vector3(1,0,0)</s>, <s>Math.PI/4</s>)		<em>// x 轴旋转</em>
<em>Object3D</em>.<b>rotateOnAxis</b>(<s>new Three.Vector3(0,1,0)</s>, <s>Math.PI/4</s>)		<em>// y 轴旋转</em>
<em>Object3D</em>.<b>rotateOnAxis</b>(<s>new Three.Vector3(0,0,1)</s>, <s>Math.PI/4</s>)		<em>// z 轴旋转</em>